Question

a large tank of water on the roof, which is open to the atmosphere
is 23 meters above a 1 cm diameter pipe with a spigot
(valve).
(a) If the spigot is turned off (no water is flowing) what is the
absolute pressure in the 1 cm pipe?
1 Pa

(b) If you open the spigot, what is the velocity of the water
coming out of the pipe?
2 m/s

(c) How long would it take for you to fill up a 20 liter bucket
(about five gallons)?
3 s